Optical Properties of Secondary Organic Aerosols Using Ultraviolet/Visible Spectroscopy
Date of Award
Restricted Access Paper
College of Arts & Sciences
Math & Science
It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. Our study aimed to discover how much radiation SOA particles absorb between ~200 and 800 nm. The SOA were created in one of two temperature controlled Teflon chambers within Dr. John Shilling’s lab at PNNL and were collected on 47 mm Teflon filters. We used an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the amount of radiation SOA absorbs at various wavelengths. We developed and optimized UV/Vis procedures for SOA dissolved in three solvent systems: water, methanol, and 0.1 M hydrochloric acid. We also successfully determined the mass absorption coefficient values and imaginary refractive indices for the generated SOA. These values will be used in climate models developed at PNNL.